1. Technical Field
The present invention relates to an adhesive for bonding inorganic glass (hereinafter simply referred to as glass unless otherwise specified) and a resin composition containing a butyl type rubber, which is useful for vehicle and building components, particularly an adhesive to be used for production of a double glazing.
2. Background Art
A butyl rubber may be used for bonding glass and another building component or bonding glass and glass for fixation at periphery of window glass for vehicle or periphery of building materials. Further, a butyl rubber may be used for sealing for a gap between glass and another building component or a gap between glass and glass, which is required to have a low moisture permeability. The reason why a butyl rubber is used for such applications is that a butyl rubber has a high adhesion, a low moisture permeability and a high weather resistance.
However, the adhesion of a butyl rubber is likely to be lowered if e.g. moisture penetrates into an interface between a substrate and the butyl rubber. Further, with regard to a composition containing a butyl rubber and various compounding agents blended therewith, the adhesion of the butyl rubber greatly depends on the physical properties of the composition. If the hardness of the composition is made high, for example, the adhesion lowers, whereby good bonding with a substrate can not be secured. A butyl rubber alone or its composition having properties close thereto, has a low modulus of elasticity, whereby it is likely to creep. A composition having a relatively large amount of compound agent blended therewith, has a high modulus of elasticity, whereby it is less likely to creep. However, the adhesion lowers, whereby the bonding with the substrate is insufficient.
When a butyl rubber is used as an edge sealing material for a double glazing, as the hardness of the butyl rubber is low, a spacer made of a metal such as aluminum is usually used, and the butyl rubber is arranged between the spacer and glass as a sealing material. The butyl rubber has a function to seal the interface between a glass plate and the spacer, to secure airtightness.
FIG. 3 is a cross sectional view illustrating the edge of the above-mentioned conventional double glazing 1. Two glass plates 1a and 1b are faced each other with a metal spacer 2 containing a drying agent 6 interposed therebetween to form a hollow layer 7, which is isolated from the open air by a primary sealing materials 3 made of a butyl type interposed between the metal spacer 2 and the glass plates 1a and 1b. The gap (concave portion) 8 constituted by outer surface of the spacer and inner surface of the periphery of the glass plates facing each other, is sealed by a secondary sealing material 5 made of a cold-setting sealing material represented by a polysulfide type or a silicone type.
A conventional double glazing employs a metal spacer, whereby the production steps of the double glazing are complicated, and it is desired to develop a double glazing having a structure with which the production steps can be more simplified. Heretofore, it has been studied and proposed to employ the folding system of the aluminum spacer for simplification or automatization of the production steps of a double glazing, or to improve the productivity by e.g. automatizing the coating of the cold-setting sealing material for reducing cost.
However, the double glazing using such a cold-setting sealing material requires a long period of time for curing the sealing material after the production of the double glazing, regardless of the type of the spacer to be used. Accordingly, the products can not be forwarded until the completion of the curing. Therefore, it is required to provide a space for curing in a plant, and to store the products for a certain period of time before forwarding, whereby it tends to take long for/ delivery, and the demands of the clients can not always be met. Further, to deal with the demands which will increase in future, more space for curing is required. To avoid this, and to secure an adequate supply of the double glazing, it is considered to be necessary to reduce the above-mentioned time for curing.
In view of reducing cost for producing the double glazing, it has been proposed to use a molded product comprising a partially-vulcanized butyl rubber composition having a drying agent incorporated therein, as a spacer (JP-B-61-20501). However, the hardness of the spacer comprising the butyl rubber-containing resin composition is not sufficient, whereby it is difficult to keep the shape of the double glazing with the spacer alone. To overcome the problem, it is considered to make the hardness of the resin composition high by blending a large amount of filler. However, in the case where the hardness is made high, the stress on the interface between glass and the spacer increases, whereby durable bonding property is not sufficient only with the adhesion of the butyl rubber.
In order to improve the physical properties of a butyl type rubber having a high adhesion by itself, the use of which is not limited to a double glazing, various compounding agents may be blended therewith, and when the composition thus obtained is bonded to glass, bonding property may sometimes be insufficient. In such a case, it is desired to employ a means of improving the bonding property, particularly the durable bonding property, of the composition to glass. The means of improving the bonding property of the resin composition containing a butyl type rubber to glass has not adequately been studied.
The present invention provides the following invention.
An adhesive for bonding inorganic glass and a resin composition containing a butyl type rubber, which comprises, as an effective component, at least one member selected from the group consisting of (A) a mixture of a terminal reactive oligomer having C4 bivalent hydrocarbon groups as repeating units with a chain extender, (B) a reaction product of a terminal reactive oligomer having C4 bivalent hydrocarbon groups as repeating units with a chain extender, (C) a mixture of a polyester polyol with a polyisocyanate and (D) a reaction product of a polyester polyol with a polyisocyanate.